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Photosensitive Epilepsy

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Biology 202
1999 First Web Reports
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Photosensitive Epilepsy

Carly Cenedella

A 17-year-old girl falls to the floor. She was playing the video game Dark Warrior. Her father, who is a video game repairman, fears that she has been electrocuted. The girl has fanatically played one game after another for years, and nothing like this has happened before. She is rushed to the hospital where doctors determine that she has had an epileptic seizure. An unusual bright flashing sequence in the game seems to have set her off (1) .

Two 13-year-old girls are playing Super Mario Brothers. When the pace of the action picks up in the third straight hour of their play, one girl starts to shake and, for three minutes, has nonstop epileptic seizures (1) .

Six hundred eighty five Japanese people ranging in age from five to fifty-eight suffer spasms, convulsions, vertigo, and breathing difficulty while watching a colorful cartoon program. Doctors determine that most were suffering from epileptic seizures induced by a flashing white light sequence during the show (2) .

In the United States, there are close to one million people with epilepsy-- about 1 in 200 people around the world have epilepsy. For most of those people, video game playing and watching television are not a risky activities. The flashing patterns of certain games and television shows trigger epileptic seizures in only 5% of epileptics (1) . Photosensitive epileptics have with a peak age of onset of 10-14 years, are mostly woman, and experience a decline in the photosensitivity after 25 years of age (3) .

In normal brain function millions of tiny electrical charges pass from nerve cells in the brain to all parts of the body. In patients with epilepsy, this normal pattern is interrupted sometimes by sudden and unusually intense bursts of electrical energy, which may briefly affect a person's consciousness, bodily movements, or sensation (4) . During a seizure, nerve cells in the brain fire electrical impulses at a rate of up to four times higher than normal. This causes a sort of electrical storm in the brain (5) . A pattern of repeated seizures is referred to as epilepsy (4) .

Seizures cause different physical effects depending on which parts of the brain are involved and how far the signals fan out. Some people have violent seizures that knock them to the floor unconscious and twitching. Others experience less severe seizures that may only blank them out for a few seconds or more. Some mild seizures pass so quickly that it seems the person is just daydreaming. But, when these "absences" happen hundreds of times a day, they can be debilitating. Often, people sense that something is about to happen to them right before a seizure. This feeling, called an "aura," makes them restless, irritable, or just vaguely uncomfortable. After a seizure, people often don't remember having the seizure (1) .

The likelihood of a seizure, as well as its type, in photosensitive individuals depends on the intensity, the contrast of the visual stimulus, and the specific frequency of flashing. Extensive EEG studies have shown that a flicker stimuli between 10 and 30 flashes per second induces the generalized epileptiform discharges and the clinical features characteristic of an epileptic seizure particularly well. Television, computer, and video game screens produce a 50 Hz flicker and a vibrating pattern at half the alternating-current frequency, or 25 flashes per second within the 10 to 30 flashes per second range. The vibrating pattern is only visible when sitting close to the television. Therefore, most television-induced seizures occur at viewing distances between 1.5 and two meters. 100 Hertz televisions cause a vibrating pattern of 50 flashes per second and do not induce seizures (3) .

Video game seizures and television-induced seizures occur in people who have heightened sensitivity to pulsing light. It is not uncommon for this so-called photosensitivity to run in families. Some drugs, like valproate, are helpful in reducing photosensitivity and preventing these seizures. Some people simply outgrow epilepsy or are able to evade seizures by avoiding the stimuli that provoke them (1) . Individuals predisposed to seizures may have an increased risk for having a seizure following stress, sleep deprivation, fatigue, insufficient food intake, or failure to take prescribed medications (4) .

Many questions arise for me when studying photosensitive epilepsy. Which area or areas of the brain are affected by the visual stimulus? It seems like the affects can be quite dispersed since the outcome can affect so many functions of the body. The person's muscles are affected. They cannot stand and often twitch. Memory is affected. The person cannot remember having the fit. The description of absences seems to suggest that alertness or wakefulness seem to be affected.

Also, what does a particular frequencies have to do with the signaling in the brain? It seems that a specific frequency, 10 to 30 flashes per second, aptly induce photosensitive seizures. Higher or lower frequencies don't have the same effect. What is it about that rate of stimulus input that affects the brain of photosensitive epileptics? Understanding the frequency effect has vast implications for understanding brain function. The rate of stimuli that a neuron or group of neuron can take in and why could tell a lot about the function of neurons in general. It must have something to do with timing-- perhaps the delay in the voltage-sensitivity in sodium ion channels plays a role.

The model that I am currently assuming in my study of epilepsy is what I call the trigger area dispersion theory. The epilepsy trigger area in the brain of photosensitive individuals is connected to the visual processing area of the brain and is sensitive to a trigger stimulus, which is a light display flashing between 10 and 30 time per second. When the trigger stimulus is presented to the photosensitive individual, the trigger area begins firing abnormally. This abnormal firing spreads to other areas of the brain. The functions served by all affected areas are compromised as the abnormal firing, the seizure, proceeds.


WWW Sources

1) The National Institutes of Health Homepage: Research in the News , written by Ruth Lew Guver

2)Health Authorities Look into Link between TV and Seizures. Medical Industry Today. December 19, 1997.

3) Trenite, D.G.A. Video Game Epilepsy. The Lancet. October 22, 1994.

4) The National Institute of Neurological Disorders and Stroke: What is Epilepsy?

5) The National Institute of Neurological Disorders and Stroke: Epilepsy



Continuing conversation
(to contribute your own observations/thoughts, post a comment below)

06/24/2005, from a Reader on the Web

Yes. I work for a company that manufactures strobe lights and one of our customers was interested in how our lights will affect his employees with epilepsy. Now I have read up on photosensitive epilepsy and how most seizures result from strobes of 5-30 Hz, however our strobes run at about 60-75 fpm (flashes per minute). This makes me feel like our strobes are not a high risk. However, we also have 60-75 qfpm (quad flashes per minute) which is somewhat similar then to 240 fpm. Would these quad flash strobes affect those with photosensitive epilepsy in the same fashion as 4 or 5 Hz strobes? Thank you.


Additional comments made prior to 2007
My sister is 22 nyears old and has had a few seizures throughout her lifetime. Her first was when she was 2 years old. She was tested for epilepsey and they said that it was a febrial seizure and she would outgrow them. The next didn't come until she was 7 years old and she was visiting my cousin after surgery. The doctor said that it was triggered by the video game they were playing. She had her next one at age 20 and she was watching an ultimate fighting show with a lot of blood. The nest happened last night when someone turned on a show of similar nature. She believes that the intense blood and nasty appearance of the faces triggered them. I have read up on the photosensitive epilepsey but they seem to have the connection with the flickering of light of the games or tv. Have there ever been similar situations where people complained that the sight of the blood could be the trigger? Is there any heredity connections? My sisters and I all have the tendency to pass out easy. I got chicken pox at the age of 24 and had a seizure that was catagorized as febrial. Now my son has them but only when he has a fever. My aunt is 50 years old and has taken dilaten since the age of 7 and is diagnosed with epilepsey. Sorry so many questions but after endless research I can't find any answers to my questions. Thank you ... Mady Schuster, 28 February 2006


Serendip Visitor's picture

My daughter has done the hand

My daughter has done the hand waving in front of her eyes/on forehead thing for at least 5 years. When outside, she will turn and face the sun and do this. When inside, overhead lights make her do this, as well.
She has had 2 grand mall seizures after doing her forehead habit in the sun.
We kept telling her neurologist that the hand waving and seizures were connected. She disagreed and told us to see a psychologist for her hand waving. We disagreed and did not do this.
Through the internet, we found "sunflower syndrome". It falls under photosensitive epilepsy. Look on the internet for some answers (most neurologists haven't heard of sunflower syndrome or won't address it). I wonder if your daughter has photosensitive epilepsy.
Through research on the internet, I found the Irlen Institute. They filter out offensive/bothersome wave lengths of light allowing the brain to function more normally and help it heal. This filtering will calm the brain and reduce stress on the central nervous system.
Based on this info, I asked our neurologist if we could test for this. She agreed. Our daughter had an EEG done. During the EEG they did the strobe light test (with eyes closed) for 5 seconds. Regular strobe light color caused immediate and definite spikes of seizure activity on the EEG monitor. Next they put a red colored disc in front of the strobe light and did the same thing. She got the same result of immediate and definite spikes of seizure activity on the EEG monitor. They also did yellow and orange, with the same results. Then they did blue, and after that green. Both the blue and green discs showed no seizure activity. It was normal!!
So if we get blue or green lenses, this should solve her light sensitivity issues! Dare we even hope that this could help or even solve her epilepsy????
We are going to contact the Irlen Institute and see if their colored lenses could help us.

Please think about having your child tested. We would NEVER have known if and what colors were triggering her!!!! For the first time, I feel empowered regarding my daughters condition!!

Serendip Visitor's picture

Thank you for sharing this information

after reading your message, I did some research on the Internet, and decided to contact the Irlen Institute. We seen a lady who does screening for them, and neither my daughter or I were convinced that it would help her (it was more geared towards reading and since my daughter doesn't have problems with reading, we didn't know if we should look into it further), none the less, we did, we seen a diagnostician last Sunday, and what an eye opener, we were there for just over 2 hours, she tried on many coloured lenses and combinations of them to determine which works best for my daughter.

The reason I say what an eye opener, is my daughter is often tired even though she gets lots of sleep. In that 2 hours, she went from feeling fine to being exhausted and not being able to make a decision. In the end, she has decided to give this a try, and after watching her in those 2 hours, I really believe that it will help her. When the diagnostician brought in a fluorescent light into the room, and my daughter was close to it, she started to feel tired and bothered by the light, causing pressure behind her eyes, which she would always complain about, and say it wasn't a headache, but it would bother her. I finally got a clearer picture of how the light affects my daughter and what a negative impact it has on her. I'm very hopeful that once we get these irlen lenses that she will finally be able to focus more in school and come home at the end of the day, not exhausted from being under the fluorescent lights all day.

Thank you so much for sharing this information with me. I would have never known about Irlen lenses without you. I am very grateful for having received this information from you.

I will let you know how it turns out, but I have a really good feeling that it will help her in more ways than one. :)

Serendip Visitor's picture

Some people with

Some people with photosensitive epilepsy become "addicted" to doing the things that cause the seizures, like playing violent video games. The experts say to try to keep them away from what they are becoming addicted too, but the sun is pretty tough. Ask ur doctor what you can do to reduce its effects.

Serendip Visitor's picture

My Sister

My sister is 56 and has been having seizures for the last 2and 1/2 years. They say she doesn't have epilepsy but she is extremely sensitive to light and especially vibration. She can't even ride in a car. Does anyone have information about this condition or know where we could get some help. We are desperately looking for a diagnosis.

Serendip Visitor's picture

Ur sister

By now you must know what it is. Though rare, some people get the symptoms of epilepsy without having it. If ur doctor allows, ask if she can take some of the medicines provided for people with photosensitive epilepsy

Serendip Visitor's picture

light sensitivity


Seizures in the car may be due to the flickering of light produced when you're driving and the sun is going through a row of trees, or when it's being reflected off water.

If your sister has seizures provoked by specific triggers, she has what is known as reflex epilepsy. It's not considered by many neurologists as a "real" form of epilepsy because, unlike typical epilepsy, the seizures don't occur without provocation. Unfortunately, there are not many physicians who know very much about it. And, unfortunately, the standard testing for light sensitivity (EEG with photic stimulation) is inadequate as well.

There are some very dark glasses that were developed by researchers to protect people with this sensitivity. The lenses are manufactured by Zeiss. See this article:

You also should check out


tracy's picture

my son

My 11 year old son seems to get these agonizing pains behind his eyes and his vision gets blurry after playing Nintendo DS video games and occasionally from playing video games on the television. He doesn't shake but ends up vomiting. He seems to be better after a short time. I noticed that about 85% of the spells happen when he is playing Nintendo DS. I have had his eyes checked which seem to be better than perfect. These spells can happen even from short periods of video use. Could he still be photosensitive and having mild seizures even though he doesn't shake and loose consiencousness?

Jessica S's picture

"spells" from Nintendo DS video games


Absolutely this sounds like seizures. It doesn't take long exposure to trigger a photosensitive seizure.
My daughter had lots of mild seizures for years from video games--and we didn't realize it. It's absolutely incredible how little known this problem is, when all our kids are exposed for hours and hours...

Check my web site:


Anonymous's picture

Photosensitive Epilepsy

I am legally blind in right eye. Even with this, I remember as a child having to shut my eyes when driving through area with trees flickering with sunlight behind them. Fast forward to exposure to workplace neurotoxins leading to coding out under surgery, some hypoxia, subsequent immune suppression and onset of chronic neuroborreliosis. Developed complex partial temporal lobe epilepsy affecting consciousness, behaviors, etc. in presence of florescent lights, CRT monitors with refresh rate of 60 hz and below. The higher the flicker rate the better the response. Bright colors on the monitors also had to be lowered, or made neutral along with contrast, and a 3M filter. Prescription 60% opacity with dark UVA/UVB anti-glare and polarizing tint necessary. Still bleed through on sides that triggers. Must avoid - and clonazepam closest to mitigating in the slightest. Research at SUNY being done on mild traumatic brain injury and migraines triggered by florescents. Also Dr. Harding's work, although my experience is that all CFL or florescents cause this problem. Indirect is more helpful, sunlight coming through windows dilutes effect somewhat, and Wal Mart, Food Lion and other naked bulbs are the worse, but even effects with sheltered and disguised bulbs. Other disabilities are effected by this, and we have found 30 years of research on Critical Flicker Frequency (CFF) in injured brain connects with this flicker. This is a barrier to entry to most facilities, and worsens as the incandescent light ban nears.

Please look at some of the research on

Any help? or do we have to bring an ADA complaint to force an amendment to help those photosensitive of us (lupus, PSE, TBI, autism, xp adversely affected by either the flicker rate and chromatic aspects or the UVA/UVB content of the lights.)

Anonymous's picture

I'm currently researching for

I'm currently researching for a mystery novel and would like to know if any of the following two set-ups might cause a seizure

- reflected, flickering light on a swimming pool in bright sunlight
wow leveling guide | watch satellite tv on pc - underwater flickering light (e.g. when the bulbs are about to burn out) in a swimming pool at night/when it's dark outside

I know, this is not a "scientific" question. I would still be greatful if you could answer me.
Thanks a lot.

Serendip Visitor's picture

A better way it is caused is

A better way it is caused is in complete darkness. Like say, night time and the light keeps flickering

Anonymous's picture

photosensitivity & seizures

flickering light from sunlight on water, etc. is a key factor for triggering seizures. The light usually has to be 'crisp' and bright. Definitely could do it for me!

Judi's picture

A type of photosensitive mild epilepsy??

I am affected by a light triggered condition that will sort of "lock me up" for a few seconds. This typically will occur in early spring, fall and winter, when trees are with minimal leaves and when the sun is setting low across the horizon. Either while I am driving, or while a passenger, the sun passes through the branches, and since I am moving, the light is basically pulsing through the near bare branches. This broken light coming in from either side, and hitting my eyes, will make me seize up for a moment, and I'll feel physically uncomfortable, until I can block this pulsing/broken light stimulus.
Any suggestions as to what this is?
Thank You!

Serendip Visitor's picture

Yes. Look up the Irlen

Yes. Look up the Irlen Institue. They have tests and glasses for this. It works!

Jane's picture

Photosensitive Epilepsy

My son was diagnosed with Photosensitive Epilepsy 3 months ago. He started rotating his eyes when exposed to the sun. After he was diagnosed the Neurologist told me about a patient (young girl) who started having seizures while driving with her parents from home to school. After investigation they discovered that the sun and the movement past the trees caused it. I think it would be a good idea if you could get an EEG to confirm your condition.
Good luck.

Alamdar's picture

Ban on Pokemon

My Brother is 12 yrs and has seizures from when he was 9 yrs.He suffered his first while watching a japanese cartoon 'pokemon'.since then he has atleast one seizure a week watching the program.After a long research also I didn't have any answer so can you plz help me?Thank You.......Alamdar Ali Mirza May 15 2008

Serendip Visitor's picture


Keep away from the program! Shows with extreme light changes such as pokemon, digimon, etc trigger seizures. The flashing light from the pokemon battles or as in japan, a rocketship taking off, can eaisly trigger seizures. While watching, where dark glasses or sit as far away from TV as posible in a completely lighted room

Mike's picture

Question causes of light induced epilepsy

I'm currently researching for a mystery novel and would like to know if any of the following two set-ups might cause a seizure

- reflected, flickering light on a swimming pool in bright sunlight
- underwater flickering light (e.g. when the bulbs are about to burn out) in a swimming pool at night/when it's dark outside

I know, this is not a "scientific" question. I would still be greatful if you could answer me.
Thanks a lot.